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Commit 21729f81 authored by Tom Lendacky's avatar Tom Lendacky Committed by Ingo Molnar
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x86/mm: Provide general kernel support for memory encryption 



Changes to the existing page table macros will allow the SME support to
be enabled in a simple fashion with minimal changes to files that use these
macros.  Since the memory encryption mask will now be part of the regular
pagetable macros, we introduce two new macros (_PAGE_TABLE_NOENC and
_KERNPG_TABLE_NOENC) to allow for early pagetable creation/initialization
without the encryption mask before SME becomes active.  Two new pgprot()
macros are defined to allow setting or clearing the page encryption mask.

The FIXMAP_PAGE_NOCACHE define is introduced for use with MMIO.  SME does
not support encryption for MMIO areas so this define removes the encryption
mask from the page attribute.

Two new macros are introduced (__sme_pa() / __sme_pa_nodebug()) to allow
creating a physical address with the encryption mask.  These are used when
working with the cr3 register so that the PGD can be encrypted. The current
__va() macro is updated so that the virtual address is generated based off
of the physical address without the encryption mask thus allowing the same
virtual address to be generated regardless of whether encryption is enabled
for that physical location or not.

Also, an early initialization function is added for SME.  If SME is active,
this function:

 - Updates the early_pmd_flags so that early page faults create mappings
   with the encryption mask.

 - Updates the __supported_pte_mask to include the encryption mask.

 - Updates the protection_map entries to include the encryption mask so
   that user-space allocations will automatically have the encryption mask
   applied.

Signed-off-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Toshimitsu Kani <toshi.kani@hpe.com>
Cc: kasan-dev@googlegroups.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/b36e952c4c39767ae7f0a41cf5345adf27438480.1500319216.git.thomas.lendacky@amd.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent fd7e3159

arch/x86/boot/compressed/pagetable.c

+7 −0
Original line number Diff line number Diff line
@@ -15,6 +15,13 @@ 
#define __pa(x)  ((unsigned long)(x))

#define __va(x)  ((void *)((unsigned long)(x)))



/*

 * The pgtable.h and mm/ident_map.c includes make use of the SME related

 * information which is not used in the compressed image support. Un-define

 * the SME support to avoid any compile and link errors.

 */

#undef CONFIG_AMD_MEM_ENCRYPT



#include "misc.h"



/* These actually do the work of building the kernel identity maps. */

arch/x86/include/asm/fixmap.h

+7 −0
Original line number Diff line number Diff line
@@ -157,6 +157,13 @@ static inline void __set_fixmap(enum fixed_addresses idx, 
}

#endif



/*

 * FIXMAP_PAGE_NOCACHE is used for MMIO. Memory encryption is not

 * supported for MMIO addresses, so make sure that the memory encryption

 * mask is not part of the page attributes.

 */

#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_IO_NOCACHE



#include <asm-generic/fixmap.h>



#define __late_set_fixmap(idx, phys, flags) __set_fixmap(idx, phys, flags)

arch/x86/include/asm/mem_encrypt.h

+13 −0
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ 


extern unsigned long sme_me_mask;



void __init sme_early_init(void);



void __init sme_encrypt_kernel(void);

void __init sme_enable(void);
@@ -28,11 +30,22 @@ void __init sme_enable(void); 


#define sme_me_mask	0UL



static inline void __init sme_early_init(void) { }



static inline void __init sme_encrypt_kernel(void) { }

static inline void __init sme_enable(void) { }



#endif	/* CONFIG_AMD_MEM_ENCRYPT */



/*

 * The __sme_pa() and __sme_pa_nodebug() macros are meant for use when

 * writing to or comparing values from the cr3 register.  Having the

 * encryption mask set in cr3 enables the PGD entry to be encrypted and

 * avoid special case handling of PGD allocations.

 */

#define __sme_pa(x)		(__pa(x) | sme_me_mask)

#define __sme_pa_nodebug(x)	(__pa_nodebug(x) | sme_me_mask)



#endif	/* __ASSEMBLY__ */



#endif	/* __X86_MEM_ENCRYPT_H__ */

arch/x86/include/asm/page_types.h

+2 −1
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 


#include <linux/const.h>

#include <linux/types.h>

#include <linux/mem_encrypt.h>



/* PAGE_SHIFT determines the page size */

#define PAGE_SHIFT		12
@@ -15,7 +16,7 @@ 
#define PUD_PAGE_SIZE		(_AC(1, UL) << PUD_SHIFT)

#define PUD_PAGE_MASK		(~(PUD_PAGE_SIZE-1))



#define __PHYSICAL_MASK		((phys_addr_t)((1ULL << __PHYSICAL_MASK_SHIFT) - 1))

#define __PHYSICAL_MASK		((phys_addr_t)(__sme_clr((1ULL << __PHYSICAL_MASK_SHIFT) - 1)))

#define __VIRTUAL_MASK		((1UL << __VIRTUAL_MASK_SHIFT) - 1)



/* Cast *PAGE_MASK to a signed type so that it is sign-extended if

arch/x86/include/asm/pgtable.h

+9 −0
Original line number Diff line number Diff line 
#ifndef _ASM_X86_PGTABLE_H

#define _ASM_X86_PGTABLE_H



#include <linux/mem_encrypt.h>

#include <asm/page.h>

#include <asm/pgtable_types.h>
@@ -13,6 +14,12 @@ 
		     cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS)))	\

	 : (prot))



/*

 * Macros to add or remove encryption attribute

 */

#define pgprot_encrypted(prot)	__pgprot(__sme_set(pgprot_val(prot)))

#define pgprot_decrypted(prot)	__pgprot(__sme_clr(pgprot_val(prot)))



#ifndef __ASSEMBLY__

#include <asm/x86_init.h>
@@ -38,6 +45,8 @@ extern struct list_head pgd_list; 


extern struct mm_struct *pgd_page_get_mm(struct page *page);



extern pmdval_t early_pmd_flags;



#ifdef CONFIG_PARAVIRT

#include <asm/paravirt.h>

#else  /* !CONFIG_PARAVIRT */